clear up in WordNet English dictionary

1. become clear
   "The sky cleared after the storm"
   clear up  clear  light up  brighten 
   
2. make clear and (more) comprehensible
   "clarify the mystery surrounding her death"
   clarify  clear up  elucidate 
   
3. free (the throat) by making a rasping sound
   "Clear the throat"
   clear  clear up 
   
4. make free from confusion or ambiguity; make clear
   "Could you clarify these remarks?"; "Clear up the question of who is at fault"
   clear  clear up  shed light on  crystallize  crystallise  crystalize  crystalise  straighten out  sort out  enlighten  illuminate  elucidate 
   
5. finish a task completely
   "I finally got through this homework assignment"
   get through  wrap up  finish off  mop up  polish off  clear up  finish up 
   

clear up in English Wiktionary